The plugin is not working properly at all

Now I have too many complaints about this plugin and unfortunately I have launched and now I'm facing a lot of issues first when any customer booked it's not showing with the color which I have mentioned and stay with the green color and I had to make it manually!!! second now when anyone go to book it show to him "the cart is empty" plz I want a quick solution since I launched the site and I'm getting so many complaints